(1) Technical Field
This invention relates to roof truss forming machines such as shown for example in my U.S. Pat. No. 3,771,439.
(2) Description of the Prior Art
Prior structures of this type may be seen in my above referred to patent and in U.S. Pat. Nos. 3,068,484, 3,069,684, 3,255,943, 3,358,348, 3,530,790 and 3,599,562. The several roof truss forming machines of the prior art required arranging of the same in a desired pattern conforming with the shape of the truss to be formed and as will be seen by referring to the above prior art patents, the machine usually employed a stationary enlongated rail with a plurality of bridges or support arms extending laterally therefrom with the actual roof truss forming machines located along the rail and on the bridges or the support arms. No prior art is known wherein individual roof truss forming machines could be freely positioned in a desired pattern on a supporting floor and temporarily securely positioned in the desired location in the pattern.
The present invention provides for the temporary secure positioning of the roof truss machines in the desired pattern by creating a seal with the supporting floor surface and then forming a partial vacuum within the area of the seal to securely attach the roof truss forming machine to the floor.